Separator



a. a. FRASER.

SEPABATOB.

APPLICATION HLED HIE-2f. 19H RENEWED DEC. 18. 19W.

1 ,3 1 7,0]. 4; Patented Sept. 23, 1919.

2 SHEETS-SHEET I.

& .9

WITNESSES: INVENTOR fl M M G. H. FRASER.

SEPARATOR.

APPLICATION FILE D 16.21. I914- RENEWED DEC. l8, I918.

Patented Sept. 23, 1919.

2 SHEETS-SHEET 2.

WITNESSES:

INVENTOR 1N8 COLUMBIA I LANouIuP" cm. autumn-mm. n. c.

GEORGE HOLT FRASER, 0F BROOKLYN, NEW YORK.

SEPARATOR.

Specification of Letters Patent.

Patented Sept. 23, 1919.

Application filed August 27, 1914, Serial No. 858,797. Renewed December 18, 1918. Serial No. 267,401.

To all whom it may concern:

llc it known that I, Gnonon HOLT FRASER, a citizen of the United States, residing at No. 226 Quincy street, in the borough of Brooklyn, county of Kings, city and State of New York, United States of America, 1nanufacturcr, have invented certain new and useful Improvements in Separators, of which the following is a specification.

This invention relates to apparatus for separating, sizing, or classifying materials by means of a fluid current, and aims to prw \idc certain improvements therein, and in processes therefor.

lleretofore it has been common to separate fine from coarse material by an air current, by past-sing the material through a casing in which the current was drawn through the material to float out the line particles and deposit these in a dust chamber, after which the current was returned and continuously reused.

With apparatus of this character it has been difficult .to prevent coarse particles from being carried out with the fine, and to prevent variations in product due to chang ing' conditions.

This invention relates to apparatus in which a fluid current is utilized to effect separation, and aims to provide improve ments whereby one or more products may be separated with greater convenience and certainty than heretofore.

To this end in carrying out the preferred form of the present improvements the material to be treated is formed into a descending blanket, alternately concentrated and expanded as it descends by gravity, intermittently retarded and rel-distributed to avoid any undue acceleration, and sufiiciently agi tated to expose all ortions to current action, and while sub ect to these conditions a fluid current is passed through it to float outwardly from the descending blanket all material capable of floating in the prevailinc; current. The remaining material descending through the current is withdrawn as tailingzs.

The extracting process to insure removal of all fine material involves the risk of carrying out some oversize, and this invention preferably provides for selecting from the extracting current such grade or grades of material as desired and insuring that the final product shall be free from objectionable sizes.

The invention further provides for nun-e completely utilising; the space necessarily occupied by the apparatus, for outside current producing provision, for rrea1or acccrv sibility, and {or convenience of cleaning, agitation and removal of parts, and it provides various features of improvement, all of which will be hereinafter more fully set forth, and described in detail intheir prc ferred form, with reference to the accompanying drawings, which illustrate the preferred adaptation of my present invention, and in which Figure l is a vertical axial section, on. pproximately on the line 1-l of Figs. "3 and 3 of an air separator constructed ac cording to the preferred form of my inven-- tion, and

Fig. 2 is a horizontal section thereof cut approximately on the planes of the lines 2-2 of Fig. 1, and

Fig. 3 is a horizontal section thereof cut approximately on the planes of the lines 3-3 of Fig. 1.

Referring to the drawings:

Let A indicate the casing, B the driving mechanism, C the feed hopper, D the distributor, E the feed chamber, F the blower, (i the dust chamber, H the return passage, I the coarse outlet, and J the fine outlet, of an air separator. All of these parts may be of any usual or suitable construction adapted to distribute the material in descend ing blanket, cause a fluid current to traverse it, precipitate the fine material floated out by the current, continuously re-use the fluid medium, and separately deliver the coarse and fine pro-ducts,

The casing A shown consists of a cylindrical body a, a flat top 6, a conical bottom 0, and a separable conical end d in which are formed the coarse and fine outlets, and all forming an inclosed chamber in which the fluid is confined.

According to one feature of my invention the driving mechanism comprises a tubular shaft K mounted in upper and lower bearings e in abracket f mounted on cross beams g which support the separator. Slidingly or rc-niovably keyed or carried on the shaft K is a cone or step wheel It driven from u similar wheel 2' by a belt j, or other suitable variable speed driving provisions.

The shaft K has a shoulder la seating on a split collar 1 which supports it vertically on a ring, ball or other non-friction annular thrust bearing m, which is centered u on and supported by lower hearing e, The

lower end of the shaft. K is reduced so that it can be passed through the vertical hearing and extends into the casing, and has screwed or otherwise separably connected to it a flange 0 to which the spider p is bolted or otherwise separably connected so as to revolve with the shaft.

The frame f is shown in Fig. 1 as open at its front side so that the shaft may be removed horizontally and then raised vertically, it and the hopper above sliding horizontally into the open side of the frame.

The hopper C is movable rotatively and adjustably mounted on the frame f and has a tubular extension Q telescopically and adjustably entering the feed pipe L, which latter is adjusted vertically b screws 1" and passes freely through the tubular shaft K opening at its lower end opposite the feed disk .9 of the distributor from which it can be adjusted to regulate or control the speed of feed. This disk is adjustably and separably connected to the spider p by screws 91, and revolves with the shaft K so that n1aterial falling on it is thrown out centrifugally and horizontally into the feed chamher.

The distributer D may be any suitable device for feeding the material in a thin blanket or wide thin stream, according to whether the blanket of material to be treated is to descend in a rectilinear or tubular path. It is preferably a driven member, and when the material is to descend by gravity in the form of a tubular blanket the distributor is preferably revolved to throw it outwardly to its path of descent.

I prefer to form the feed chamber E as a circular or annular chamber surrounding the distributor and bordered by a baffle plate shown as a cylindrical ring 6 against which the material strikes and which is removable for renewal.

Below the baflie ring my invention preferably provides a contractin or feeding ring or plate u, u on which t 1e material falls from the ha to ring and by which it is directed inwardly and delivered onto the first of a series of retarding or distributing rings or members '0 which check the speed of flow and deflect the material outwardly allowing it to fall onto a second converging or defleeting ring or plate u down which the material flows and from which it falls onto the next plate 1), the contracting and discharging plates or rings being arran ed in succession so that the material will ow down one and fall onto the other, be retarded thereby and a ain fall onto the next, and so on throu out the series of feeding plates where y the material descending by gravity between them traverses a sinuous path and is alternately retarded and re-started so that undue acceleration of speed of flow is prevented and suflicient agitation is obtained, as the material descends between the plates. When these are arranged in ring form as shown the material descending between them constitutes an endless blanket or tubular envelop between the distributor and the tailiugs cone M below them, and the space between the rings or plates constitutes an annular sinuous separating passage N.

The rings 1) are relatively short and the rings u are preferably long or upwardly extended to bring their upper edges above the lower edges of the next upper ring 1), and preferably to or above the lower edge of the next up )er ring a, so that the current in passing etween two rings u must rise as it traverses the passage and any heavy particles carried out horizontally by it may be dropped onto the upper part of the ring a as the current rises to pass over the top thereof.

For some work where further selection is unnecessary the seri s of rings a and 1 only may be used in ronneclion with the current producing and dust collecting provisions, but I prefer to provide for further selecting the material thus separated, and preferably for separately classifying or grading these selections according to their number. My invention )rovides for this one or more successive se ectors, preferably annular and parallel with the primary feeding and retarding members and concentric with and surrounding these intermediate of the pressure and exhaust chambers. Preferably this is accomplished in the manner shown by interposing a reversely inclined plate or ring to opposite each passage 0 which intercepts the outflowing current and deflects it downwardly at an acute angle, and by interposing the succeeding plate or ring an outwardly of and spaced apart from the adjacent rin n; which again intercepts the current and deflects it upwardly, so that the current travels approximately horizontally and preferably slightly upwardly in a sinuous path as it expands outwardly, and large pieces carried by it will be intercepted and fall or be thrown out of it as the current turns around the edges of the rings w and w in passing these. These rings are slightly spaced apart above and below each passage to permit particles thus precipitated or selooted to descend between them and are sufliciently spaced apart to give the desired width of passage for the current. Particles extracted between these rings will descend crossing the current for each succeeding passage so that should any fines escape with them the current of a succeeding passage may extract these.

These rings or lates constitute a selector R, and their pro uct may be separately received and withdrawn by a selector cone S through a passage T and outlet U.

Ordinarily one selector succeeding the initial separating device will suflice, but for some purposes a plurality of successive selectors, or differential classifiers or graders, may be desirable, and my invention preferably comprises two or more of these between the final and initial extracting, which is preferably accomplished providing another plate or ring :1; in the passage '0 beyond the selector R, which again deflects the outflowing current downwardly against a cone or wall a. The current from the several passages O discharges within this wall and flows upwardly over the top of the wall and down into the chamber Q. This wall 2 constitutes a'second selector 'V,the tailings of which maybe separately collected as shown by a cone Wand passage X and outlet Y when this grade is desired.

Proportioning, inclination, relative elevation, and intermediate spacing, of these several parts will be suited to circumstances or requirements, but are preferably such as to effect varying current speeds as well as considerable changes of direction in the current as it progresses outwardly, and in 'the final selection chamber the area is suflicient to give such volume as will insure a current speed suited to float only particles of the fineness desired in the finest product to be produced so that only this will be carried into the chamber Q and can reach the dust chamber G. p

In the chamber Q the current descends with comparative slowness, its floating dust being precipitated by gravity into the set fling chamber for removal through the fine outlet.

The air is withdrawn from the chamber Q or returned to the chamber P through the return assage H, which communicates between tl iese and preferably exhausts by suction from the inner side of the chamber Q. I preferably for better disclosing their utilization, illustrate my present improvements as used in connection with my improved means for mechanical extraction or filtration of floating particles from the fluid intermediate of the chamber Q, and the return H in which I prefer to provide a forai ninous or interstitial wall between these through which the current must pass, and this is preferably a double wall or series of hollow troughs or plates disposed with their concave sides facin the chamber Q and their convex sides faclng the inlet H and extending downwardly and outwardly from the cone W constituting the top wall of the return, the cone a constituting its bottom wall. These plates 2) are staggered" in relation and spaced apart so that circuitous passages c exist between them through which the current may flow while their hollow faces will provide a space in which particles may settle and descend without danger of being floated by eddies into the stron current before they reach the dust 'cham er.

Any suitable current producing means and connection may be utilized with those features of my improvements already described, but I prefer to employ an outside blower or one separate from and independent of the feeder, and to drive this and the letter from the same source of power, referably a motor Z, coupled to the shaft of the blower F, which shaft is shown as extended to the pulley a for driving the feeder.

" The suction and discharge connections between the outside blower and the chambers Q, and P may be made in any suitable way, but according to the preferred form of my invention I provide for utilizing centrifugal action to equalize the outflow and inflow of current and avoid undue variations or inequalities thereof, and to preserve a uniform L suction throughout the exhaust chamber Q. This is preferably accomplished by connecting the suction pipe e of the fan tangentially with an annular exhaust passage f outwardly of and surrounding the distributing and contracting inlet g of the return and communicating with the latter by a reverse passage it over an intermediate annular dam i, so that the suction current from the trough f will cause a rapid whirling action in the latter which will prevent excessive withdrawal of air at any one point around thes'inuous annular passages communicatilnlg between this and the inlet passage 7.

My invention provides a similar means for utilizing centrifugal force to equalize the blast as the current comes from the blower to the chamber P which is preferably accomplished by connecting the blast pipe j of the blower tangentially to an annular blast chamber k in which the blast will whirl and uniformly discharge over the inner wall or cone Z and down through the passage m to the open end a of the main tailings cone M, through which as it rises itwill still be subjected to some whirling action which will aid in avoiding excess of current at any one point. r in "In" this way an outside blower as distinguis "ed from one inclosed within the casing and revolving with the distributor may be utilized at a great saving of power and much simplification of construction, and the desired blower and distributer feeds and lid adjustments may be had independently; and the blower need not be subjected to great weer frem direct contact with the material, as it can operate only on the cleanest air. My invention rovides for utilizing much of the space within the bottom cone which is not all needed for precipitation cit dust, and preferably accomplishesthis by locating both the annular suction chamber and its communicating passages, and the annular blast chamber, and its communicating passages as well as the intermediate selector passages, all within the dust chamber, and the blast chamber Within the suction-chamber, so that these all are concentrically superposed and compactly nested around the tailings' and selector passages, and the blower may be placed where desired and suitably connected with them.

When used as separate passages the selector passages are preferably disposed between the suction and blast equalizers by a series of cones spaced apart to giee the necessary intermediate passage'an'd suitably connected and separated for convenience and manipulation. As shown the cone 0 held on the cone d serves as the inner wall of the dust chamber G and connects with theoutlet Y and with the secondary selector passage X. Loosely setting on it is a reversecone 31' serving as the stop of the latter passage and the innerwall of the suction chamber f and loosely setting on this is a cone q constituting one outer wall of the latter, the top wall of which isthe cone 2", all of these cones being suitably supported and mounted so that each can, be vibrated or lifted and are movable for cleaning. 7

When'my present im rovements are used with my'improved filter as shown, the inner troughs 157' are preferably rigidly connected to the cone W and supported at their lower ends against the cone 0: but the OHQQIIEIQW of troughs are movably or elastically; connected at their upper ends to the cone W as by springs 0 which poise them resiliently so that they may quiver in use to clean themselves, and their lowerends bear against the cone 0. The cone 0 is preferably sectionalized by a section f separably connected so that it can be removedqto permit the removal of the interior cones.-

'Where advisable the edges of the cones are slightly spaced to permit settlings to drift through and where necessary their edges are valved with, aiflap d or flexible stripto avoid current leakage while permitting gravity flow of precipitated material.

The outer wall of the blast chamber-hears a cone a carrying the outlet I and serving as the inner wall of the assage T and on this cone is mounted t e cone )3 which serves as the top wall of the blast chamber and isolates it from the passage. The cone M serves as one iener'wall oi the blast chan gassagesT and X between the cone 1) her and the reverse cone a as its bottom wall. Between the cones c and 0 is a cone a used when the tailings from each selector are to be separated and which constitutes the intervening wall between their outlets, on which cone is aeone'w partitioning the and 1e cone 3. While these cones may be fixel together 51 prefer to loosely separably and suitably. connect and support them so that theynmay be readily vibrated, adjusted or removed. The spacers between them constitute impact or jarring posts or members, .by hammering on which 'percussively they maybe vibrated to loosen adhering material. Adj ustable separable screws 2 under the cones 0 of and 8" support these.

My invention provides for accessibility to the several parts of the device by the operator Without substantial. manipulation, and for this purpose I preferably construct the tailings outlet I with a large tubular passage at" closed by a cover 2: by opening which a man can crawl in and pass through the interior of the separator. to adjust, repair or clean it. Similarly the suction and blast passages e.' and j are made respectively with a door a in direct line with them and of sufficient, size to permit entrance of the body so that the operator can crawl in either the suction or exhaust'equalizer.

Several cones are preferably suspended by rods A from the top brand positioned centrally by divergent bars a and b" irom the side. V

In operation the speed of feed entering from the hopper C will be controlled by adjusting the: feed pipe L toward the feed disk 8 or by regulating the speed of the latter by its driving mechanism. The current will be controlled by the speed of the fan or bye butterfly valve B or otherwise. The removable cones t andnu will be used if the selector tailings or either of them are to be separately withdrawn.

,Current rising into the chamber P will flow out-between the rings 4), traverse the blanket of descending material, extract the fines and float them out through the passage O.- The selectors R and V when and if used will make their. proper selections and classifications, and the floating'fines passing these will descend through the chamber Q and fall into the dust chamber G, the air carryingthese being drawn through the filter (when my present improvements are used in connection with thisland clarified on its way to the return passage H. The exhaust through the latter will be uniform. Any sediment settling within the exhaust chame ber will leak through the cracks thereof and fall into the'dust chamber. The blast by reason of its centrifugal action will exert a uniiiorm pressure as it flows over and under the walls and rises within the cone M and into the chamber P. Any dust settling in the blast passage will leak through into the main taillngs outlet. The feed and withdrawal will be constant, and once adjusted to the work operation may continue without change regardless of variations in quan tity or quality. A suflicient current to insure complete extraction can be used without danger since the selectors will eliminate any large particles blown out at the first extraction. Efliciency will be increased when my present improvements are used in connection with my improvements in internal filtration.

It will be seen that my invention provides improvements which can be readily and advantageously availed of and it will be understood that the invention is not limited to the particular details of construction, arrangement or combination of parts, set forth as constituting its preferred embodi ment since it can be utilized in Whole or in part according to such modifications as circumstances or the judgment of those skilled in the art may dictate without departing from the spirit of the invention. 2

When feed to the hopper 0 includes material too coarse for passing through the separator a scalper C is used, which may be any suitable scalper, but, for better disclosing my present improvements I have illustrated them as used in connection with my improvements in scalping means'which comprise a slotted foraminous plate or screen bent into steps intermediate of the longitudinal extent of its elongated slots, so that the lower bent portion constitutes an outlet for each slot to permit escape of nails or hanging pieces, which is disposed with its long faces or steps at approximately 45 degrees inclination and its intermediate portions at approximately right angles thereto, and mounted in a trough or chute B of greater inclination than the scalper, and which is preferably combined with a dam or retarder D opposite each step to prevent too rapid flow. The large pieces scalped out of the feed descend past the separator to a spout E.

The suction and blast pipes are separably connected to the blower, and the corresponding passages of the blower are provided with separable walls or hinged manhole doors 2 see Fig. 3, so that either can be opened or removed for access.

The scalper, having slots narrower than the selector outlets, guards these against possible oversizes;

-For the purpose of more completely disclosing the scope and applicability of the features incident to this invention which I refer to claim in this application many natures of improvement in separating, sizing and collecting machinery are herein shown and set forth but not specifically claimed in this a plication, being the subjects matter-of c aims in my applications Serial Numbers:

267,402 filed December 18 1918 (being a renewal of my original application 859,004 filed August 28, 1914) 859,145 filed August 29, 1914;

29,705 filed May 21, 1915;

69,024 filed December 28, 1915;

69,025 filed December 28, 1915;

104,706 filed June 20, 1916;

181,538 filed July 19, 1917;

231,599 filed A ril 30, 1918;

235,914. filed Milly 22, 1918;

281,445 filed March 8, 1919;

307,417 filed June 28, 1919;

307,418 filed June 28, 1919;

310,328 filed July 12, 1919;

910,329 filed July 12, 1919;

316,799 filed Aug. 11, 1919.

What I claim is:

1. In combination, a casing, means outside of said casing for causing a fluid current to flow therein, means for causing material to descend therein in a downward path across the direction of flow of such cur rent, extracting means in said casing comprising upwardly and downwardly extending members at one side of said path having a lower outlet for coarse particles and affording between them an outwardly extending sinuous current passage successive to said downward path of such descending material for receiving said current beyond said path for extracting coarse particles carried by said current, a settling chamber succeeding said extending means and in communication with said passage, and means communicating between said settling chamber and the other side of said path.

2. In combination, a casing, means outside of said casing for causing a fluid current to flow therein, means for causing material to descend therein in a downward path across the direction of flow of said current, extracting means comprising. upwardly and downwardly extending members affording a lower outlet for coarse particles and affording a plurality of horizontally extendin sinuous current passages for receiving sai current successive to the downward path of such descending material for extracting coarse particles carried by said current, and a settling chamber succeeding said extracting means and in free communication with two of said passages.

3. In combination, a casing, means outside of said casing for causing a fluid current to flow therein, means for causing material to descend therein in a downward path across the direction of flow of said current, selecting means within said casing at one side of said path comprising upwardly and downwardly extending members providing a lower outlet for coarse particles and a horizontally extending sinuous current passage for receiving said current successive to the downwardpath, of such desceuding material for extracting coarse particleS carried by said current, a settling chamber succeeding said selecting means and in communication with said passage. and means affording an adjustable return passage communicating between said settling chamber and the interior of said casing at the other side of said path.

4. In combination a casing, means outside of said casing for causing a fluid current to flow therein, means for causing material to descend therein in a downward path across the direction of flow of said current, means within said casing and at one side of said path providing alower outlet for precipitated material and affording a sinuous passage for receiving said current successive to the downward path of such descending material for extracting particles carried by said current, and means atfording a closed return passage receiving current leaving said sinuous passage and 1eturnin it to the interior of said casing at the ot or side of said path;

5. In combination, a casing, means outside of said casing for causing a fluid current to flow therein, means for causing material to descend therein in a downward path across the direction of flow of said current, selecting means within said casing providin a lower outlet for coarse particles and aifording a sinuous current passage for re ceiving aid current successive to the down ward path of such descending material for extracting coarse particles carried by said current, a settling chamber succeeding said selecting means and in communication with said passage, a return passage, means affording a downward conduit for coarse material descending through said. path, and

means affording a separate downward conduit for particles extracted by said selecting means,

6. In combination a casing, means outside of said casing for causing a fluid current to flow therein, means for causing material to descend therein in a downward pathacross the direction of flow of said current, selecting means at one side of said path providing a lower outiet for precipitated particles and affording a sinuous current passage for receiving said current successive to the downward path of such descending material for extracting coarse particles carried by said current, means alfording a downward passage, communicating with-said passage, succeeding said selecting means, means affording a settling chamber below and communicating with said downward passage, and means affording a current outlet from said dqwnward passage intermediate of its extremities.

7. In combination, a casing, means outi side of said casing for causing a fluid current to flow therein, means for causing material to descend therein in a downward path across the direction of flow of said current, selecting means providing a lower outlet for precipitated particles and affording a sinuous current passage for receiving said current successive to said path for extracting coarse particles carried by said current, supplementary selecting means providing a lower outlet for precipitated material and affordin a sinuous current passage for receiving said current from and successive to said first mentioned sinuous passage for extracting particles carried by said current, a settling chamber succeeding said supplementary selecting means and in free communication with said sinuous passage thereof, and a return conduit for said current.

8. In combination, a casing, means outside of said casing for causing a fluid current to flow the-rem, means for causing material to descend therein in a downward path across the direction of flow of said current, selectin means at one side of said path comprisin a plurality of upwardly and downwar 1y extending superposed members providing lower outlets for precipitated particles and affording superposed sinuous current passages for receiving said current successive to said downward path for extracting particles carried by said current, and means affording a current passage successive to and communicating with a plurality of said sinuous passages receiving current therefrom for delivering it to the other side of said path.

9. In combination, a casing, means outside of said casing for causing a fluid current to flow therein, means for causing material to descend in a downward path in said casing across the direction of flow of said current, selecting means within said casing at one side of said path roviding a lower outlet for particles and a ording a horizontally extending sinuous current passage for receiving said current successive to the downward path of such descending material for extracting particles carried by said current, 5 and means affording a communicating passage recelvm current from said sinuous passage and elivering it to the other side of said path.

10. In combination, a casing, means outside of said casin for causing a fluid current to flow therein, means for causing material to descend therein in a downward path across the direction of flow of said current, selecting means in said casing at one side of said path affording a sinuous current passage successive to said downward path for receiving said current beyond said path for extracting particles carried by said current and affording an outlet for such particles below an intermediate portion of said passage, a settling chamber underneath said selecting means and in communication with said passage, and means below said selecting means afl'ording a partition between the latter and said settling chamber.

11. In combination, a casing, means out- Side of said casing for causinga fluid current to flow therein, means forcausingmaterialto descend therein in a downward path across the direction of said flow, selecting means at one side of said path affording a sinuous current passage successive to said path for receiving said current beyond said path for extracting particles carried by said current and afl'ording an outlet for such particles below an intermediate portion of said passag a chamber successive to said selecting means and in communication with said passage, means aflording a return passage communicating between said chamber and the other side of said path, and means below said selecting means afl'ording a wall or partition between the latter and said return passage.

12. In combination, a casing, means outside of said casing for causing a fluid current therein, means for causin material to descend therein in a downwarc path across the direction of flow of said current, selecting means at one side of said path afl'ordin a sinuous current passage successive to sai path for receiving said current beyond said path for extracting particles carried by said current and affording an outlet for sucli particles below an intermediate portion of said passage, a dust chamber successive to and receiving current from said sinuous passage, and means affording a re turn passage above said dust chamber for returning such current above the latter to the other side of said path,

13. In combination, a casing, means for causing material to descend therein in an an nular path, means for causin a fluid current to traverse such descen ing material, an annular dust chamber surrounding said path, an annular return chamber inwardly of and surrounded by said dust chamber and connnunicating therewith, a tangential conduit leading from said return chamber, a blower connected at its suction side to said conduit, and a return pipe communicating between the blast side of said blower and the interior of said casing inwardly of such descending material.

14. In combination, a casing, means for feeding material thereto, means for causing such material to descend therein in an annular path, a blower outside of said casing for causing a fluid current to flow outwardly across such path, selecting means within said casing surrounding said path comprising reversely inclined walls providing a lower outlet for particles and afi'ording a sinuous current passage for receiving said current successive to said path for extracting coarse particles carried by said current, an annular passage successive to and receivin such current from said sinuous passage an aflording communication between the outer extremity of said sinuous passage and the inner side of said path.

15. In combination, a casing, means outside of said casing for causing a fluid current to flow therein, means for causin material to descend therein in an annular ownward path, annular selecting means outwardly of and concentric of said path and comprising reversely inclined walls providing a lower outlet for precipitated particles and affording a sinuous outwardly extending current passage for receiving said current successive to said path for extracting coarse particles carried by said current, an annular chamber successive to and communicating with said sinuous passage for receiving current. therefrom, and means below said selecting means afl'ording communication between said annular chamber and the space within said annular path.

16. In combination, a casing, means outside of said casing for causing a fluid current to How therein, means for causing material to descend therein in an annular path, means comprising a pluralit of spaced annular walls surrounding sai ath and providing a lower outlet for precipitated material and a sinuous current passage at the outer side of said path for receiving said current successive to said path for extracting coarse particles carried by said current, an annular chamber successive to and in free communication with said sinuous passage, and means affording a communicating passage between said chamber and the space within said annular path.

In witness whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

EDMUND J. FENN, CHRISTIAN MATHISEN.

copies at this patent may be obtained for five cents each, by addressing the "Commissioner of Patents. Washington, I). 0." 

